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This is the 1.5mm 4130 flat and rails for the M85 kits that are out. It's basically just our standard M70 underfolder flat without the pin holes cut for the recoil assembly locking pin. The center support will have to be clearanced to fit the .223 magazines.
The magwell size is made to fit original Yugo 5.56 magazines. Aftermarket magazines or ones from other countries may be narrower.